Surgical anastomosis is to join together two hollow organs, usually to restore continuity after resection, or less commonly to bypass an unresectable disease process. Anastomosis is typically performed on blood vessels including arteries and veins, gastrointestinal tract including esophagus, stomach, small intestine, colon, rectum, bile ducts and pancreas, urinary tract including ureters, urinary bladder and urethra, and fallopian tubes.
Colorectal anastomosis surgery is one of the most commonly performed intestinal surgical anastomosis (“Surgical Treatment of Rectal Cancer”, Bleday R. et al, The ASCRS Textbook of Colon and Rectal Surgery, 2007, Springer, New York, page 413-436). Historically, laparotomies (open surgery) are performed. During the surgical procedure, after dissecting the colon from the rectum and resecting the diseased segment, such as cancerous tissue, from the colon, the two dissected open ends are manually sutured together. This is a time-consuming and often very difficult process. Particularly, when the diseased segment is located at the extreme low end of the rectum, which is deep in the lowest part of the pelvis, it can be extremely difficult to manually access the dissecting site. Under such circumstances, the surgery has a higher risk of anastomotic leakage, which causes severe infectious complications and often requires reoperation for an abscess, fistula, peritonitis, or a permanent colostomy (bringing the colon out through the abdominal wall so that waste can be collected in a bag rather than by evacuating stool through the anus).
In the past few decades, linear and circular surgical staplers have been developed and mechanically stapled methods are increasingly used in colorectal surgeries. The stapled colorectal anastomosis is faster and often more convenient for the surgeon to operate. However, various complications have been associated with stapled colorectal anastomosis. In the stapled colorectal anastomosis procedure, the linear and circular stapled areas overlap, which increases the risk of leakage at the interface between the linearly stapled area and the circularly stapled area. It has been reported in numerous publications that the instances of colorectal strictures in stapled anastomosis are statistically higher than in sutured colorectal anastomosis (“Stapled anastomosis after colorectal resection for benign and malignant disease”, Raidoo, S N et al, S Afr Med J. 1984, 66(21):819-21; “Handsewn vs. stapled anastomosis in colon and rectal surgery: a meta-analysis”, MacRae, H M et al, Dis Colon Rectum. 1998, 41(2):180-9; “Results of reoperations in colorectal anastomotic strictures”, Schlegel R D et al, Dis Colon Rectum. 2001, 44(10): 1464-8; “Anastomotic dehiscence in colorectal surgery, Analysis of 1290 patients”, Pronio, A et al, Chir Ital. 2007, 59(5): 599-609.)
More recently, laparoscopic colorectal anastomosis surgery method has been developed. With the laparoscopic method, a small cut is made on the lower abdomen, an endoscopic linear cutting stapler is inserted into pelvic cavity to transect the rectum, and a circular stapler is subsequently used to perform a colorectal colocolic, ileorectal, or ileoanal anastomosis. Laparoscopic colorectal anastomotic procedures have the advantages of a small wound, less trauma, and an overall faster patient recovery. However, the inherent problems from the stapled colorectal anastomosis remain in laparoscopic stapled anastomosis procedures. Furthermore, in laparoscopic colorectal anastomosis procedures, the head of the linear stapler can only be operated in a range from 0° to about 45° from the shaft. When the site for transection is in the distal rectum, it can be very difficult to transect the rectum with the linear cutting stapler. Typically, two or three sequential progressive stapling and cutting cartridges are required to transect the lower rectum. Each cut requires removing the stapler from the abdominal cavity and loading a new cartridge to the head of the stapler. This multifire approach is not only time consuming, but also a higher risk of complications and anastomotic leakage.
Therefore, there exists a strong need for improved tools and surgical methods to reduce the risks associated with existing sutured and stapling methods for anastomosis to improve operability under difficult conditions, to improve quality and outcome of the anastomosis and to reduce the cost of an anastomosis surgery.